(±)-3[alpha],5[alpha]-Bis(methoxycarbonyl)-3[beta]-methyl-6[alpha]-phenyltetrahydro-2H-pyran-2-one

The structure determination of the title compound, dimethyl (±)-3[beta]-methyl-2-oxo-6[alpha]-phenyl-3,4,5,6-tetrahydro-2H-pyran-3[alpha],5[alpha]- dicarboxylate, C₁₆H₁₈O₆, unequivocally establishes its relative stereochemistry. The results provide strong support for the proposal that enolates derived from cis-5,6-disubstituted tetrahydro-2H-pyran-2-ones react very selectively with electrophiles trans to the C(5) and C(6) substituents.

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